Lack of laminin gamma1 in embryonic stem cell-derived cardiomyocytes causes inhomogeneous electrical spreading despite intact differentiation and function.
Laminins form a large family of extracellular matrix (ECM) proteins, and their expression is a prerequisite for normal embryonic development. Herein we investigated the role of the laminin gamma1 chain for cardiac muscle differentiation and function using cardiomyocytes derived from embryonic stem cells deficient in the LAMC1 gene. Laminin gamma1 (-/-) cardiomyocytes lacked basement membranes (BM), whereas their sarcomeric organization was unaffected. Accordingly, electrical activity and hormonal regulation were found to be intact. However, the inadequate BM formation led to an increase of ECM deposits between adjacent cardiomyocytes, and this resulted in defects of the electrical signal propagation. Furthermore, we also found an increase in the number of pacemaker areas. Thus, although laminin and intact BM are not essential for cardiomyocyte development and differentiation per se, they are required for the normal deposition of matrix molecules and critical for intact electrical signal propagation.
Malan
Daniela
D
Institute of Physiology I, Life and Brain Center, University of Bonn, Germany.
Reppel
Michael
M
Dobrowolski
Radoslaw
R
Roell
Wilhelm
W
Smyth
Neil
N
Hescheler
Juergen
J
Paulsson
Mats
M
Bloch
Wilhelm
W
Fleischmann
Bernd K
BK
D000200:Action Potentials; D000818:Animals; D001485:Basement Membrane / Q000378:metabolism; D015820:Cadherins / Q000378:metabolism; D002454:Cell Differentiation; D003599:Cytoskeleton / Q000378:metabolism; D004553:Electric Conductivity; D053595:Embryonic Stem Cells / Q000166:cytology*; D005109:Extracellular Matrix / Q000378:metabolism; D016023:Integrins / Q000378:metabolism; D007797:Laminin / Q000172:deficiency*; D051379:Mice; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000378:metabolism*; D015854:Up-Regulation
D015820:Cadherins; D016023:Integrins; D007797:Laminin; C089141:laminin gamma 1